FR2599358A1 - Pulverulent dry compositions, process for their preparation and process for the manufacture of opacifying glass pastes from these compositions - Google Patents

Abstract

Pulverulent dry compositions made up of particles of opacifying glass and of a dry gelling agent such as an organic titanate. …<??>These ingredients are mixed to obtain a dry composition which is mixed with an organic carrier to obtain a thixotropic opacifying glass paste.

Description

PULVERULENT AND DRY COMPOSITIONS. PROCESS FOR

THEIR PREPARATION AND PROCESS FOR THE MANUFACTURE OF PASTA

OF BLOCKING GLASS, FROM THESE COMPOSITIONS

The present invention relates to powdery and dry compositions, containing particles of sealing or sealing glass and a gelling agent; these compositions are useful for the subsequent preparation of a thixotropic paste and not subject to

sedimentation or settling.

In US Pat. No. 4,444,813 in the name of the same Applicant, a process for preparing a glass paste, thixotropic and sealing, is described in a workshop by mixing on site glass particles for sealing and a vehicle. A liquid organic which preferably consists of amyl acetate and nitrocellulose, and which contains, in a state of dispersion, a liquid organic gelling agent. Although the described process is highly advantageous and solves the problems connected with the manufacture and use of the pulp, there still remains a problem of shelf life of the starting materials in store, as well as a problem of transportation. of the liquid organic vehicle due to its toxicity and possible instability if exposed

to heat during transport.

Consequently, the main objects of the present invention are to provide: - a pulverulent composition, dry and stable, comprising particles of sealing glass and a dry gelling agent, and which does not pose a conservation problem and is easy. and convenient to carry; a composition which is a mixture, pulverulent and dry, of glass blocking particles and a dry gelling agent, and subsequently giving, in an organic vehicle, a suspension which does not settle; - a process for the manufacture of a powdered and dry composition, intended to be subsequently mixed with an organic vehicle to give a thixotropic paste, which process consists of (a) taking dry particles of sealing glass and a gelling agent , dry and powdery, the dimensions of the glass particles being about 1 to 150 microns and (b) mixing the glass particles with the agent to obtain a dry composition in which said agent is at least about

0.001% by weight of the powder composition.

These and other objectives will emerge from the

description which will follow.

The present invention provides a composition which is a powdered, dry mixture of glass sealant particles and a dry gelling agent, and subsequently forming, in an organic vehicle, a suspension.

which does not settle.

The preferred powdery composition is a mixture, dry powdery, of sealing glass particles, approximately 1 to 150 microns in size, and a dry gelling agent, which comprises an organic caking agent deposited on an inert vehicle. having particle sizes of about 2 to 150 microns, the gelling agent being used in an amount effective to subsequently provide, in an organic vehicle, a suspension of the composition which does not settle

not under the effect of gravity.

The present invention also provides a process for preparing a powdered and dry composition, for subsequent mixing with an organic vehicle to form a thixotropic paste, which process comprises (a) taking dry sealing glass particles and a dry, powdery gelling agent, the size of the glass particles being about 1 to 150 microns; and (b) mixing the glass particles and the agent to obtain a dry composition in which the agent is at least about 0.001% by weight of the powder composition. The present invention also provides a process for preparing a thixotropic sealant paste, which process comprises preparing the dry composition, described above, of sealant glass particles and a dry gelling agent. , and mixing the powder composition with an organic vehicle to

obtain a paste which does not settle.

Appropriate particles of shutter glass

are described in US Patents 4,365,021 and 4,522,925.

US Patent 4,444,813 describes a process allowing

to extend the store shelf life of a thixotropic glass sealant paste. The present invention is an improvement of US Patent 4,444,813.

This patent describes gelling agents which are suitable for the present invention provided that they are dry gelling agents or agglomerating agents.

Preferred dry agents are glomerating organic titanates, especially isopropyl tri (dioctylpyrophosphato) -titanate and other alkyl tri (dioctylpyrophosphato) titanates, the alkyl group of which has from 1 to

carbon atoms.

A suitable dry gelling agent is a chemical reagent called CAPAW L12 / H, manufactured by Kenrich Petrochemicals Co. Its chemical name and formula are: tri (dioctylphosphato) -neoalkyltitanate; (A '/ OCsH RO - Ti (O P) 3

(

(\ OCsHl?) () This titanate is deposited on the surface of particles of

silica, which gives a preferred dry source of the reagent.

Example:

A pulverulent and dry composition is prepared by dry mixing L12 / H with solder glass powder. The tests show no noticeable detrimental effects on the critical properties of the glass. The powder is placed in a transport container and 7% by weight vehicle (consisting of regular frit of nitrocellulose and amyl acetate) is added to the container and the container is rotated for 60 minutes to obtain the paste. . The tests carried out on the dough demonstrate the thixotropic rheology of the latter. The optimal doping rate is found to be 10 or 20 up to 30

ppm L12 / H.

Example Frit Friti Properties 51318 10 ppm (t ATD (440 C Iso.) Of] Peak time (min) 22.0 Completion time (min) 27.0 Button flow

(440 C - 60 ') 1.099

Rod seal stress (440 C - 60 ') 140 c Crystallization index 3.0 The solder glass particles are sealing containing approximately the following: Ingredients% Wt Pbo 75.2 Zno 12.1

B203 8.2

S102 2.2

BaO 1.9 Zircon 0.4 te + Dorant 0.001% wt) L12 / H, 0.5 1.090 280 c 3.5 in one glass Ingredients, 0 The powder compositions provide very effective sealing glass pastes which possess rheology thixotropic, with flow under the effect of a

shearing and subsequent return to the initial state.

The powder compositions, illustrated by the example, offer the following advantages: 1. Transport in powder form instead of the much more dangerous transport in paste form.

containing a toxic vehicle.

2. Easy preparation of the dough, on site, by the user, using normally available vehicles such as amyl acetate and

nitrocellulose.

3. Elimination of the problem of too short a shelf life of a pre-made dough or a

doped vehicle.

4. Cost reduction.

The above advantages are obtained with particles of sealing glass and inert silica, coated with the dry gelling agent, of dimensions included in the following general and preferred fields: General Preferred sealing glass 1 to 150 microns 10 to 38 microns Silica 2 to 150 microns 10 to 38 microns In general, the sealing glass particles have

an average size of about 10 to 20 microns.

Although the organic & caking agent, i.e. titanate, which is used in the example is preferred, other gelling agents can also be employed, such as those described in US Patent 4,444. .813, in place of all or part of the titanate, which gives substantially equivalent results. In general, when gelling agents such as bentonite, colloidal silica, aluminosilicate clays, etc. are used, they are used in greater proportions, for example 2 or 3 to 5 times, than those of titanate. organic. The dry gelling agent is generally about 10 to 50 ppm (0.001 to 0.005% by weight), of the total powder composition. The preferred proportion is about 20 to 30 ppm (0.002 to 0.003% by weight) of the gelling agent in the powdered and dry composition, with admixture thereof with the organic vehicle. As explained in US Pat. No. 4,444,813, the organic vehicle can represent about 5 or 6, up to 8 or 9% by weight of the dough, with a preference for a proportion of 7 to 8% by weight. , as indicated

in column 4 of this patent.

Claims (11)

1. Composition, characterized in that it is a mixture, powdery and dry, of glass blocking particles and a dry gelling agent, and subsequently yields, in an organic vehicle, a suspension that does not settle. 2. Composition according to claim 1, characterized in that the sealing glass particles have dimensions of approximately 1 to 150 microns and in that the dry gelling agent comprises an organic agglomerating agent, deposited on a support. inert having particle sizes of about 2 to 150 microns, the gelling agent being used in an amount effective to subsequently provide, in an organic vehicle, a suspension of the composition which does not settle. not under the effect of gravity. 3. Composition according to claim 1 or 2, characterized in that the gelling agent comprises an agglomerating agent, powder and titanium, and an inert vehicle of silica particles, the agent being used in an amount sufficient to give by then, in an organic vehicle, a suspension of the composition which does not settle. 4. Composition according to claim 3, characterized in that said agent is isopropyl tri (dioctylpyrophosphato) titanate. 5. Composition according to Claim 3, characterized in that the agent is an alkyl tri (dioctylpyrophosphato) titanate in which the alkyl group contains from 1 to 10 carbon atoms, and in that the organic vehicle is based on amyl acetate and nitrocellulose. 6. Composition according to claim 1, characterized in that the gelling agent represents at least about 0.001% by weight of the powder composition. 7. A method of manufacturing a dry and pulverulent composition, intended to be subsequently mixed in an organic vehicle to give a thixotropic paste, characterized in that it consists: (a) in taking dry particles of sealing glass and a gelling agent, powdery and dry, the dimensions of the glass particles being about 1 to 150 microns; and (b) mixing the glass particles and agent to obtain a dry composition wherein said agent is at least about 0.001% by weight of the powder composition. 8. A method according to claim 7, characterized in that it comprises the additional step (c) of mixing the dry composition in an organic vehicle to form a paste consisting of a suspension, which does not settle, of particles. of glass in an organic vehicle, this vehicle representing approximately 5 to 10% of the dough weight. 9. Process for the preparation of a thixotropic paste which becomes fluid under shear and which subsequently recovers its previous viscosity, characterized in that it consists (a) in mixing dry particles of sealing glass with a dry agent of gelation, to obtain a composition workshop mixing the organic, to form the workshop. 10. Composition characterized in that at 0.005% of the weight of the 15 11. Composition characterized in that at 0.003% of the weight of the pulverulent and dry, and (b) in dry composition with a vehicle the paste usable on site in according to claim 3, the agent represents approximately 0.001 pulverulent composition. according to claim 3, the agent represents approximately 0.002 powder composition.